Replacing capacitors in soundcard Echo AudioFire with bigger caps 8

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Hi PH104,
Many thanks for the link!

This really doesn't seem to be a great way to check a capacitor. The normal LCR bridge and LCR meters made by HP / Agilent / Keysight, Genrad and a few others are the only reliable way to test a capacitor. They pretty much say you can't test caps in-circuit. You can't by any method really except for maybe ESR. ESR is of limited usefulness in signal circuits, and dissipation is more accurate to indicate the health of a capacitor. Dissipation is 1/Q.

Vloss will be greatly affected by the input impedance of the meter used to measure it, and as the range changes that resistance will change also. Humidity might make a huge difference with the smaller capacitors. Measuring frequency should be in the area where the capacitor is expected to be effective.

Robert, don't waste any more money using this test. It is hopelessly inaccurate and impossible to calibrate it against the quality of a capacitor. It will mislead you for sure.

-Chris
 
Yes is not accurate at all to use such devices but when I swapped out those REC caps and measured the Vloss I also measured the Vloss of those replacing them .

With this tester a REC cap haing 100uf 6,3v have up to 12% Vloss so I replaced those with Nichicon FG 100uf 10v those measuring almost 0 usually between 0,3 and 0,5 Vloss on this tester for the new caps . So I think the tester in not really a joke and is pretty serious . Also the FMs and FCs did showed very low Vloss under 0,5% .

The problem with this cheap tester is with big caps not having enough power to measure those with accuracy .
 
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That doesn't mean the caps are shot. What was the ESR compared to the datasheet spec? You are most likely wasting your time.
Let me check the official pdf datasheet specs .
For REC SR cap series no ESR info is offered and for REC LZ the same.
If I make some measurements regarding ESR.
REC LZ 100UF 25V ESR 0.60 OHM
REC SR 100UF 6.3V ESR 1.4 OHM.
REC SR 1000UF 6.3V ESR 0.6 OHM

REC SR 220UF 10V ESR 0.97 OHM
REC LZ 470UF 10V ESR 0.55 OHM
REC LZ 100UF 16V ESR 0,74 OHM (this is the only one on specs)
Don't call me paranoid:). Those are not ok . From 6 only one is still on specs.I won't measure all but will replace all for safety I don't trust this REC brand.

Until now I replaced almost 30 and sounds much normal . Before that the sound was not ok . I started the mod because the sound revealed the problem .
 
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Hi Robert,
I rarely measure ESR. For power supply capacitors I look at the waveform across the capacitor. For audio or signal capacitors, I measure dissipation. Simple, direct and easy.

Of course, the quality of the instrument does determine how accurate the answers you get are. You can't forget that.

-Chris
 
Chris the board have over 50 caps .From those only a few are on specs and the rest of 90% are measuring mediocre to worst .
First I refused to believe that my soundcard sounded bad so I lied my self but didn't worked with me such trick so I took a good CD player and a DVD player and made A B blind tests and noticed that ECHO sounded more tiny with less detail and poor resolution compared to the other sources .
Right now sounds very accurate .Each cap is soldered on both side of the board so is difficult to change such caps .
 
Let me check the official pdf datasheet specs .
For REC SR cap series no ESR info is offered and for REC LZ the same.
If I make some measurements regarding ESR.
REC LZ 100UF 25V ESR 0.60 OHM
REC SR 100UF 6.3V ESR 1.4 OHM.
REC SR 1000UF 6.3V ESR 0.6 OHM

REC SR 220UF 10V ESR 0.97 OHM
REC LZ 470UF 10V ESR 0.55 OHM
REC LZ 100UF 16V ESR 0,74 OHM (this is the only one on specs)
Don't call me paranoid:). Those are not ok . From 6 only one is still on specs.I won't measure all but will replace all for safety I don't trust this REC brand.

Until now I replaced almost 30 and sounds much normal . Before that the sound was not ok . I started the mod because the sound revealed the problem .

Those values seem in line with what I would expect from cheap electrolytic capacitors. I doubt they are all bad. If you want to know the truth you need to take some measurements of the analog outputs before and after the change.
 
C'mon there should be a standard right ?. Especially the cheapo coupling caps for the outputs where the same non polar REC type. Those can be seen in the photos having that purple color . So I think those are filtering the output signal for each output ?. I replaced those with Nichicon ES so probably the main improvement comes from this .
 
You cannot test a capacitor in circuit, unless you know how to carefully calculate the result of all the rest of the circuit. I am going to guess that you do not know how to do this, and may not even realise that this was necessary. Hence all your 'in-circuit' capacitor checks, however they were done, are null and void. You have almost certainly been changing capacitors which did not need to be changed. 'Vloss' is a meaningless measure, not used by any serious electronics engineer. It is likely that any perceived improvement is due to expectation bias, while any perceived degradation is due to overheating components with the soldering iron.
 
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